This paper is focused on the results of the Rb–Sr isotope dating of gold-bearing quartz–sericite–dolomite altered wall-rock (beresite) at the Kekura deposit, Western Chukotka. The results obtained constrain the temporal relationship between ore formation and the emplacement of granodiorite. Due to the fine-grained nature of the metasomatic rock, a density fractionation was used to separate mineral sample for subsequent isotope study. The Rb–Sr isochron yields an age of 111.4 ± 1.1 Ma for altered wall-rock, which is consistent with the U–Pb zircon age of 110.6 ± 1.2 Ma obtained from the same sample. The established age of the rocks indicates an absence of a significant time gap between the granodiorite intrusion and the hydrothermal alteration processes associated with gold mineralization at the Kekura deposit. These findings provide a strong evidence for a relation of the studied processes within a single ore-forming system.
Nagornaya et al. (Sun,) studied this question.